CN1219401C - A method for preventing illegal broadcasting in cable digital TV broadcasting - Google Patents
A method for preventing illegal broadcasting in cable digital TV broadcasting Download PDFInfo
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- CN1219401C CN1219401C CN 03102681 CN03102681A CN1219401C CN 1219401 C CN1219401 C CN 1219401C CN 03102681 CN03102681 CN 03102681 CN 03102681 A CN03102681 A CN 03102681A CN 1219401 C CN1219401 C CN 1219401C
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Abstract
The present invention relates to a method for preventing illegal broadcasting in cable digital TV broadcasting, which belongs to the technical field of a signal transmission safety technique. The present invention is characterized in that a transmitting party inserts a control message into a transfer layer at a definite time; a receiving party detects the control message after physical layer phase demodulation and before de-interleaving, judges the legitimacy of broadcasting data and receives or rejects the control message. The present invention can realize a method for preventing illegal broadcasting for a receiver conforming to the design of the method and prevent the illegal broadcasting from destroying television and broadcasting industry in a country. The present invention is also compatible with receivers which do not adopt the method in the current market so that the receivers in the current market can normally receive television signals.
Description
Technical field
Prevent that the method for illegal broadcasting belongs to signal transmission security technical field in a kind of cable digital TV broadcasting, particularly the signal transmission security technical field in internet, Digital Television, the data broadcasting.
Background technology
In the past few years, along with the transformation of simulated television to Digital Television, Digital Television will become an important transmission productive life information, enrich the high-tech product of mass culture life.TV signal is a kind of important public information resource, has play a part very important for people's daily life, production and culture progress.Destroy the malicious act of public information safety and occurred some at present, for example on June 23rd, 2002 to June 30, overseas Falun Gong cult is under the manipulation and commander of Li Hongzhi, and illegal transmitted radio signal is attacked my prosperous promise satellite.The Chinese Central Television's 9 programs and 10 provincial station synchronizations in " the village village is logical " radio and television engineering of transmitting on this satellite repeater are subjected to serious interference, and the part rural area and the outlying mountain area masses can't normally watch news, meteorology, flood situation forecast, world cup soccer finals and other programs.This interference broadcast TV programme is normal to be broadcasted and the normal activity of using of breaking the law on a serious scale of satellite, has violated the basic norm of relevant international convention and commercial communication, threatens the national security, and has invaded public's rights and interests.For the baneful influence that prevents that this illegal broadcasting from producing, in the cable digital TV broadcast technology that China is about to promote, should adopt the technological means of protection public information safety, prevent that illegal television broadcasting from producing ill effect, the protection public interest.
Prevent in a kind of cable digital TV broadcasting as herein described that the method for illegal broadcasting from adopting transmit leg regularly to insert the control preface at transport layer, before deinterleaving, the recipient detects the control preface after physical layer phase demodulating, judge the legitimacy of broadcast data, make the processing that receives or refuse.This is based on a kind of security means on the cable digital TV broadcast technology basis of standard.
Summary of the invention
The object of the present invention is to provide the method that prevents illegal broadcasting in a kind of cable digital TV broadcasting.
The invention is characterized in: regularly insert control information in the transport stream of transmitting terminal in cable digital TV broadcasting, receiving terminal is after phase demodulating, before deinterleaving, detect the control information of regulation, extract control information, the legitimacy of checking broadcast transmitter is done the processing that receives or refuse; It contains following treatment step successively:
(a). produce the control information of long 120 bits (15 byte), byte number is 1～15; Control information is divided into synchronously, address field, controlling packet counting, reserve broadcast channel, CRC check, totally 5 fields; Wherein synchronization field length is 32 bits, takies the 1st, 2,3,4 byte of 15 byte control informations, and the sequential value of synchronization field is shown 5D 8F 9A43 with 16 system numerical tables; The address field field length is 16 bits, take the 5th, 6 byte of 15 byte control informations, adopt the extended hamming code coding, wherein address code takies wherein the 1st to the 11st bit, the Hamming check sign indicating number takies wherein the 12nd to 15 bit, and the even parity check sign indicating number takies wherein the 16th bit; Controlling packet count area length is 8 bits, takies the 7th byte of 15 byte control informations, count value 0～255 circulation; Reserving the broadcast channel field length is 48 bits, takies the 8th to 13 byte of 15 byte control informations; The CRC check field length is 16 bits, takies the 14th, 15 byte of 15 byte control informations, is used for the CRC check to the control information of whole 15 bytes, and its generator polynomial is g (x)=x
16+ x
12+ x
5+ 1;
(b). produce 8 kinds of pre-scrambling modes, every kind of pre-scrambling mode has 15 bytes, is used for pre-scrambling is carried out in the control information of above-mentioned 15 bytes;
(c). according to randomisation process will be compatible mutually with satellite system among the GB/T 17700-1999 principle, the transport stream that is made of the MPEG-2 bag is carried out the data scrambling randomization, it also contains following step successively;
(c.1). the MPEG-2 bag that carries control information after regulation is inserted is fixed as one group of i bag in 8 MPEG-2 bag, wherein 1≤i≤8;
(c.2). 15 bytes of the j kind in 8 kinds of pre-scrambling modes that produce in the control information of 15 bytes of step (a) generation and the step (b) are carried out handling by the bit XOR, 1≤j≤8 wherein, and j is corresponding with the position i of MPEG-2 bag, obtains 15 byte control informations through pre-scrambling;
(c.3). being mapped to one through the control information of pre-scrambling not in the MPEG-2 bag with user data, this MPEG-2 bag is provided with the special identifier that empty bag sign or setting and receiving terminal are arranged; Each bag is made of 188 bytes, through control information the from the 1st to the 15th byte order of 15 bytes of pre-scrambling, divide other the 13rd, 25,37,49,61,73,85,97,109,121,133,145,157,169,181 bytes that are mapped to this MPEG-2 bag; Controlled bag;
(d). the transport stream of the cable digital TV of standard is at first carried out the filtering of sky MPEG-2 bag, and the MPEG-2 bag behind the empty bag of filtering is flow to row cache; Multiplexing and rate adapted module is used for the MPEG-2 bag stream and the controlling packet of multiplexing buffer memory output, assurance is inserted controlling packet with the interval every 2 milliseconds in MPEG-2 bag stream, guarantee in 8 transmission package of each group, the controlling packet of inserting only may occur the on i position of wrapping, in order to keep certain transmission rate, when input rate is too small, insert the sky bag of some in the multiplex process, when input rate is excessive, abandon some packets; Obtain through inserting the transport stream that controlling packet is handled;
(e). carry out the synchronous counter-rotating of the cable digital TV of standard through the transport stream of inserting the controlling packet processing, the scrambling randomization, coding and convolutional interleave are handled;
(f). the transport stream of handling through the coding and the convolutional interleave of standard is carried out single channel encryption handle, adopt the variable pseudorandom scrambling of initial state, its generator polynomial is g (x)=x
19+ x
5+ x
2+ x+1,11 bit address sign indicating numbers of control information and 8 bag count values are carried out scrambling to the transmission package between current controlling packet and the next controlling packet, not scrambling of controlling packet as 19 bit initial states after controlling packet of every insertion; To carry out the sign map and the modulation treatment of the cable digital TV of standard through the transport stream of encryption, send;
(g). in receiver, at first the transport stream that receives is carried out the demodulation process of the cable digital TV of standard, at this moment also do not make deinterleaving and channel decoding and handle, tentatively obtain digital signal from radiofrequency signal; In transport stream, pass through the transmission package packet header of examination criteria, identify transmission package one by one, then i the signal packet with the transmitting terminal agreement in 8 signal packet of every frame detected, if on the 13rd, 25,37,49,61,73,85,97,109,121,133,145,157,169,181 bytes of signal packet, identify the control information of prescribed form, the expression data flow is a legitimate traffic, normally receives data; If at a period of time t within second of regulation, fail to detect the appearance of the control information of prescribed form always, be indicated as invalid data stream, the rejection data, and continue to detect control information.
At 8 kinds of pre-scrambling modes described in the step (b), every kind of usefulness 16 system numbers are expressed as follows from the 1st byte to the 15 byte orders:
The 1st kind: 73 A1 2B B4 9D, 86 3B, 30 25 3A FB, 63 F7 EA 7D
The 2nd kind: 71 2E A7,84 32 A3,76 41 D8 DB, 19 CC 52 38 05
The 3rd kind: FC 56 91 50 68 CF 66 C7 1F 41 07 9D AA 97 58
The 4th kind: 56 37 E3 B6 9A 6A 9B, 53 08 56 6A, 45 2A A8 62
The 5th kind: D5 E8 DF B0 99 DF C4 53 74 63 58 99 29 EE D7
The 6th kind: 38 D4 DC, 73 73 52 C1 6F, 81 8A, 36 DA, 25 9F 08
The 7th kind: C1 98 94 1D 97 D2 7D 8A BE BA B5 53 00 A9 F3
The 8th kind: C2 D5 9E 6A 3D E0 D6 03 66 19 66 E1 33 96 E5.
Described insertion controlling packet be spaced apart 2 milliseconds, corresponding to different transmission rates, insert a controlling packet in the transmission package of the multiple per 8; When being 6.528 MBPSs, the speed that requires the transport stream after process is inserted controlling packet in per 8 transmission package, inserts a controlling packet; When being 13.056 MBPSs, the speed that requires the transport stream after process is inserted controlling packet in per 16 transmission package, inserts a controlling packet; When being 19.584 MBPSs, the speed that requires the transport stream after process is inserted controlling packet in per 24 transmission package, inserts a controlling packet; When being 26.112 MBPSs, the speed that requires the transport stream after process is inserted controlling packet in per 32 transmission package, inserts a controlling packet; When being 39.168 MBPSs, the speed that requires the transport stream after process is inserted controlling packet in per 48 transmission package, inserts a controlling packet; When being 52.224 MBPSs, the speed that requires the transport stream after process is inserted controlling packet in per 64 transmission package, inserts a controlling packet.
Described receiving terminal is by detecting controlling packet, and therefrom the cycle of extracting is 2 milliseconds a timing information, is used for Network Synchronization
In described (c) the controlling packet production process in step, the bag sign of controlling packet that is used to carry control information is by transmitting terminal and receiving terminal agreement.
Experimental results show that: the present invention has prevented the illegal broadcast message of external insertion effectively.It also realizes compatibility for general receiver.
Description of drawings:
Fig. 1 standard cable digital TV transmits and receives the structured flowchart of machine;
The transmission packet structure schematic diagram of Fig. 2 MPEG-2;
Fig. 3 a MPEG-2 transmission package
Fig. 3 b randomization transmission package: sync byte and randomized sequence
Fig. 3 c RS (204,188, T=8) sign indicating number error protection bag
Fig. 3 d interlacing frames: interleave depth I=12 byte
In Fig. 4 standard cable digital TV randomization with remove the randomization theory diagram;
Convolutional deinterleaver and deinterleaver theory diagram in Fig. 5 standard cable digital TV;
Fig. 6 cable digital TV that contains the control signal insertion and detect of the present invention transmits and receives the structured flowchart of machine;
The structural representation of the control signal among Fig. 7 the present invention;
The structural representation of the address field in the control signal among Fig. 8 the present invention;
The schematic diagram of the single channel encryption process among Fig. 9 the present invention;
Embodiment:
We are the signal processing of the cable digital TV broadcast technology of description standard at first, as shown in Figure 1.
In the transmitter of the cable digital TV broadcast technology of standard, what import is the MPEG-2 code stream of standard, the MPEG-2 code stream is made up of the MPEG-2 bag of one by one 188 bytes, and to wrap by the packet header of 4 bytes and the payload of 184 bytes be that data constitute to each MPEG-2 as shown in Figure 2; The packet header of 4 bytes is divided into again: the bag sign of sync byte of a byte (47H) and 15 bits, and the bag sign is used to discern the type of bag, and other control informations of some bits; We have only applied to sync byte and bag sign in this patent;
In the transmitter that the cable digital TV of standard is broadcasted, the MPEG-2 code stream of the standard of input is through the input of base band physical interface, at first pass through sync byte (syncl) counter-rotating and randomization, as Fig. 3 a is the MPEG-2 bag that does not also pass through sync byte (syncl) counter-rotating, syncl is exactly sync byte 47H, SYNC1 represents not randomized sync byte radix-minus-one complement among Fig. 3 a, Fig. 3 b, Fig. 3 c, Fig. 3 d, be B8H, SYNCn represents not randomized sync byte, be 47H, n=2 wherein, 3,, 8.
As Fig. 3 b is the schematic diagram of one group of 8 transmission package of counter-rotating of process sync byte and randomization, the difference of transmission package and MPEG-2 bag only is, the sync byte of MPEG-2 bag all is 47H, transmission package is that 8 bags are one group, wherein the sync byte of first bag is B8H, they are 188 bytes, the definition compatibility of other fields; System's input code flow is a MPEG-2 bag, carries out randomization by structure shown in Figure 3, and is compatible mutually with satellite system among the GB/T 1770-1999.The generator polynomial of carrying out randomized pseudo-random binary sequence (PRBS) is as follows:
1+x
14+x
15
As shown in Figure 4, the PRBS counter of when the beginning of per 8 transmission package sequence " 100101010000000 " being packed into makes its initialization.In the group of one 8 bag length, the sync byte 47H of first bag becomes B8H by the bit paraphase from 47H, and handling like this is for an enabling signal being provided for the receiver descrambler.First of exporting in first byte after first bit is made transmission package sync byte (B8H) with paraphase of PRBS carries out XOR, then other bits of Shun Xu effect.In order to realize other synchronizing function, the duration of the sync byte of 7 follow-up transmission bags, PRBS works on, but its output is invalid, these sync bytes is not carried out randomization.Like this, the cycle of PRBS sequence is 1503 bytes.Randomized result is shown in Fig. 3 b, in 8 transmission package of each group, the sync byte of first bag is reversed to B8H, and the sync byte of other 7 bags remains 47H, all asynchronous bytes in 8 transmission package are randomized, promptly with the PRBS sequence by the bit XOR.
In the transmitter that the cable digital TV of standard is broadcasted; carry out the RS coding of standard through the transmission package after sync byte (syncl) counter-rotating and the randomization; obtain RS (204; 188; T=8) sign indicating number error protection bag; here each packet length is 204 bytes; wherein preceding 188 bytes are the transmission package content; do not change, back 16 son joints are for error protection joint, shown in Fig. 3 c; our invention does not relate to RS coding and decoding process; the theory and the technology of RS coding can be referring to " error correcting code-principle and methods ", Xian Electronics Science and Technology University, work such as Wang Xinmei.
In the transmitter that the cable digital TV of standard is broadcasted, carrying out convolutional interleave through RS coded data stream handles, interleave depth is 12 bytes, convolutional interleave and corresponding deinterleaving processing procedure are as shown in Figure 5, transmission package behind the convolutional interleave is shown in Fig. 3 d, and our invention does not relate to the convolutional interleave processing procedure, and the theory of convolutional interleave and technology can be referring to " error correcting code-principle and methods ", Xian Electronics Science and Technology University, work such as Wang Xinmei.It should be noted that because in our controlling packet, control information is to leave on the 13rd, 25,37,49,61,73,85,97,109,121,133,145,157,169,181 bytes of the controlling packet of 188 bytes, after through RS coding and convolutional interleave processing, information on these bytes does not have the variation of occurrence positions, make that we can just extract these control informations at receiver end before RS decoding and convolution de-interleaving, RS decipher and convolution de-interleaving before just can judgment data legitimacy receive or refuse processing.
In the transmitter that the cable digital TV of standard is broadcasted, carry out byte to the conversion of m bit sign through the data flow that convolutional interleave is handled, differential coding, base band shaping, the processing of QAM modulation and IF and RF physical interface sends on the physical channel.
In the receiver that the cable digital TV of standard is broadcasted, from the signal of physical channel, through RF and IF physical interface and qam demodulator, matched filtering and equilibrium, differential decoder, symbol tentatively obtains byte stream to the mapping of byte;
In the receiver that the cable digital TV of standard is broadcasted, through convolution de-interleaving, RS decoding is reversed synchronously and is gone and flows from base band physical interface output MPEG-2 bag after the randomization, gives the digital TV decoding device processes.
The present invention is in the cable digital TV broadcast technology of standard, and transmitter regularly inserts control information at transport layer, detects control information before receiver deinterleaves after physical layer phase demodulating, judges the legitimacy of broadcast data, makes the processing that receives or refuse; The meaning of Chu Liing is like this, the receiver that meets this patent design is realized a kind of method that prevents illegal broadcasting, prevent that illegal broadcasting from destroying China's television, and for the receiver that does not also adopt this patent design in the market, also realize compatibility, make its normally received television signal.Its signal processing as shown in Figure 6; Its processing procedure is as follows:
The first step, the control information that produces long 120 bits (15 byte), as shown in Figure 7, byte number is 1～15; Control information is divided into synchronously, address field, controlling packet counting, reserve broadcast channel, CRC check, totally 5 fields; Wherein synchronization field length is 32 bits, takies the 1st, 2,3,4 byte of 15 byte control informations, and the sequential value of synchronization field is shown 5D 8F 9A 43 with 16 system numerical tables; The address field field length is 16 bits, takies the 5th, 6 byte of 15 byte control informations, adopts the extended hamming code coding, as shown in Figure 8, wherein address code takies wherein the 1st to the 11st bit, and the Hamming check sign indicating number takies wherein the 12nd to 15 bit, and the even parity check sign indicating number takies wherein the 16th bit; Controlling packet count area length is 8 bits, takies the 7th byte of 15 byte control informations, count value 0～255 circulation; Reserving the broadcast channel field length is 48 bits, takies the 8th to 13 byte of 15 byte control informations; CRC (CRC) check field length is 16 bits, takies the 14th, 15 byte of 15 byte control informations, is used for the CRC check to the control information of whole 15 bytes, and its generator polynomial is g (x)=x
16+ x
12+ x
5+ 1; According to the CRC code encoding method of standard, its cataloged procedure is, regards information bit as multinomial, and for example information bit is 1001, and then corresponding multinomial is s (x)=x
3+ 1, s (x) be multiply by x
16, getting 16 here is because CRC code check bit number is 16, again it is made polynomial division promptly
Wherein q (x) is that s (x) multiply by x
16After the part that can be divided exactly by g (x), r (x) is the part that can not be divided exactly by g (x), is s (x) * x to the result behind the CRC coding of information s (x) then
16+ r (x), it can be divided exactly by g (x), receiver carries out polynomial division to it, whether it divided by g (x), by analyzing its remainder, just can check data mistake have been occurred in transmission, these all are the methods of the CRC sign indicating number of standard, the theory of CRC sign indicating number and technology can be referring to " error correcting code-principle and methods ", Xian Electronics Science and Technology University, work such as Wang Xinmei.
Second step produced the pre-scrambling mode of 15 bytes, was used for pre-scrambling is carried out in the control information of 15 bytes that as above produce, and the pre-scrambling mode of 15 bytes has 8 kinds, is expressed as follows from the 1st byte to the 15 byte orders with 16 system numbers:
The 1st kind: 73 A1 2B B4 9D, 86 3B, 30 25 3A FB, 63 F7 EA 7D
The 2nd kind: 71 2E A7,84 32 A3,76 41 D8 DB, 19 CC 52 38 05
The 3rd kind: FC 56 91 50 68 CF 66 C7 1F 41 07 9D AA 97 58
The 4th kind: 56 37 E3 B6 9A 6A 9B, 53 08 56 6A, 45 2A A8 62
The 5th kind: D5 E8 DF B0 99 DF C4 53 74 63 58 99 29 EE D7
The 6th kind: 38 D4 DC, 73 73 52 C1 6F, 81 8A, 36 DA, 25 9F 08
The 7th kind: C1 98 94 1D 97 D2 7D 8A BE BA B5 53 00 A9 F3
The 8th kind: C2 D5 9E 6A 3D E0 D6 03 66 19 66 E1 33 96 E5
The 3rd step, the transport stream of the cable digital TV of standard is to be made of the MPEG-2 bag, to carry out the data scrambling randomization to transport stream, its randomisation process can be compatible mutually with the satellite system among the GB/T17700-1999, be that per 8 MPEG-2 bag is as one group, the sync byte of first MPEG-2 bag is reversed to B8H from 47H, gives enabling signal of scrambler, uses the scrambling mode of regulation to carry out scrambling to per 8 MPEG-2 bag; The MPEG-2 bag that carries control information after regulation of the present invention is inserted is fixed as i bag in these 8 MPEG-2 bags, wherein 1≤i≤8; Here pre-scrambling is carried out in the control information of 15 bytes that just first step produced, be about to its with second step in 15 bytes of j kind in 8 kinds of pre-scrambling modes producing carry out by the processing of bit XOR 1≤j≤8 wherein, and corresponding with i; Obtain 15 byte control informations through pre-scrambling; To be mapped to through 15 byte control informations of pre-scrambling in the MPEG-2 bag that does not carry user data, this MPEG-2 bag is provided with the special identifier that empty bag sign or setting and receiving terminal are arranged; Each bag is made of 188 bytes, through control information the from the 1st to the 15th byte order of 15 bytes of pre-scrambling, divide other the 13rd, 25,37,49,61,73,85,97,109,121,133,145,157,169,181 bytes that are mapped to this MPEG-2 bag; Controlled bag;
In the 4th step, the transport stream of the cable digital TV of standard is at first carried out the filtering of sky MPEG-2 bag, and the MPEG-2 bag behind the empty bag of filtering is flow to row cache; Multiplexing and rate adapted module is used for the MPEG-2 bag stream and the controlling packet of multiplexing buffer memory output, assurance is inserted controlling packet with the interval every 2 milliseconds in MPEG-2 bag stream, guarantee in 8 transmission package of each group, the controlling packet of inserting only may occur the on i position of wrapping, in order to keep certain transmission rate, when input rate is too small, insert the sky bag of some in the multiplex process, when input rate is excessive, abandon some packets; Obtain through inserting the transport stream that controlling packet is handled;
The 5th step, carry out the synchronous counter-rotating of the cable digital TV of standard through the transport stream of inserting the controlling packet processing, the scrambling randomization, coding and convolutional interleave are handled, as Fig. 3 a, Fig. 3 b, Fig. 3 c, Fig. 3 d, Fig. 4 and shown in Figure 5;
The 6th step, the transport stream of handling through the coding and the convolutional interleave of standard is carried out single channel encryption handle, adopt the variable pseudorandom scrambling of initial state, its generator polynomial is g (x)=x
19+ x
5+ x
2+ x+1,11 bit address sign indicating numbers of control information and 8 bag count values are as 19 bit initial states, and the scrambling process is carried out scrambling to the transmission package between current controlling packet and the next controlling packet, not scrambling of controlling packet as shown in Figure 9 after controlling packet of every insertion; To carry out the sign map and the modulation treatment of the cable digital TV of standard through the transport stream of encryption, send;
The 7th step, in receiver, at first the transport stream that receives is carried out the demodulation process of the cable digital TV of standard, at this moment also do not make deinterleaving and channel decoding and handle, tentatively obtain digital signal from radiofrequency signal; In transport stream, pass through the transmission package packet header of examination criteria, identify transmission package one by one, then i the signal packet with the transmitting terminal agreement in 8 signal packet of every frame detected, if in the 13rd of signal packet, 25,37,49,61,73,85,97,109,121,133,145,157,169, identify the control information of prescribed form on 181 bytes, the expression data flow is a legitimate traffic, the normal data that receive, be decrypted processing, encryption corresponding to above the 6th step, described encryption and decryption is handled and is equal to a kind of descrambling operation that adds, add the descrambling process as shown in Figure 9, carrying out the deinterleaving and the channel decoding of the cable digital TV of standard afterwards again handles, obtain the MPEG-2 code stream at last, give the digital TV decoding device processes; If at a period of time t within second of regulation, fail to detect the appearance of the control information of prescribed form always, be indicated as invalid data stream, the rejection data, and continue to detect control information.
Characteristics of the present invention and effect:
Transmit leg regularly inserts control information at transport layer, and reciever detects control information before deinterleaving after physical layer phase demodulating, judges the legitimacy of broadcast data, makes the processing that receives or refuse; The meaning of Chu Liing is like this, the receiver that meets the present invention's design is realized a kind of method that prevents illegal broadcasting, prevent that illegal broadcasting from destroying China's television, and also realize compatibility for the receiver that does not also adopt the present invention to design in the market, make its normally received television signal.
Claims (5)
1. prevent the method for illegal broadcasting in the cable digital TV broadcasting, it is characterized in that: regularly insert control information in the transport stream of transmitting terminal in cable digital TV broadcasting, receiving terminal is after phase demodulating, before deinterleaving, detect the control information of regulation, extract control information, the legitimacy of checking broadcast transmitter is done the processing that receives or refuse; It contains following treatment step successively:
(a). produce long 15 bytes, the control information of totally 120 bits, byte number is 1～15; Control information is divided into synchronously, address field, controlling packet counting, reserve broadcast channel, CRC check, totally 5 fields; Wherein synchronization field length is 32 bits, takies the 1st, 2,3,4 byte of 15 byte control informations, and the sequential value of synchronization field is shown 5D 8F9A 43 with 16 system numerical tables; The address field field length is 16 bits, take the 5th, 6 byte of 15 byte control informations, adopt the extended hamming code coding, wherein address code takies wherein the 1st to the 11st bit, the Hamming check sign indicating number takies wherein the 12nd to 15 bit, and the even parity check sign indicating number takies wherein the 16th bit; Controlling packet count area length is 8 bits, takies the 7th byte of 15 byte control informations, count value 0～255 circulation; Reserving the broadcast channel field length is 48 bits, takies the 8th to 13 byte of 15 byte control informations; The CRC check field length is 16 bits, takies the 14th, 15 byte of 15 byte control informations, is used for the CRC check to the control information of whole 15 bytes, and its generator polynomial is g (x)=x
16+ x
12+ x
5+ 1;
(b). produce 8 kinds of pre-scrambling modes, every kind of pre-scrambling mode has 15 bytes, is used for pre-scrambling is carried out in the control information of above-mentioned 15 bytes;
(c). according to randomisation process will be compatible mutually with satellite system among the GB/T 17700-1999 principle, the transport stream that is made of the MPEG-2 bag is carried out the data scrambling randomization, it also contains following step successively:
(c.1). the MPEG-2 bag that carries control information after regulation is inserted is fixed as one group of i bag in 8 MPEG-2 bag, wherein 1≤i≤8;
(c.2). 15 bytes of the j kind in 8 kinds of pre-scrambling modes that produce in the control information of 15 bytes of step (a) generation and the step (b) are carried out handling by the bit XOR, 1≤j≤8 wherein, and j is corresponding with the position i of MPEG-2 bag, obtains 15 byte control informations through pre-scrambling;
(c.3). being mapped to one through the control information of pre-scrambling not in the MPEG-2 bag with user data, this MPEG-2 bag is provided with the special identifier that empty bag sign or setting and receiving terminal are arranged; Each bag is made of 188 bytes, through control information the from the 1st to the 15th byte order of 15 bytes of pre-scrambling, divide other the 13rd, 25,37,49,61,73,85,97,109,121,133,145,157,169,181 bytes that are mapped to this MPEG-2 bag; Controlled bag;
(d). the transport stream of the cable digital TV of standard is at first carried out the filtering of sky MPEG-2 bag, and the MPEG-2 bag behind the empty bag of filtering is flow to row cache; Multiplexing and rate adapted module is used for the MPEG-2 bag stream and the controlling packet of multiplexing buffer memory output, assurance is inserted controlling packet with the interval every 2 milliseconds in MPEG-2 bag stream, guarantee in 8 transmission package of each group, the controlling packet of inserting only may occur the on i position of wrapping, in order to keep certain transmission rate, when input rate is too small, insert the sky bag of some in the multiplex process, when input rate is excessive, abandon some packets; Obtain through inserting the transport stream that controlling packet is handled;
(e). carry out the synchronous counter-rotating of the cable digital TV of standard through the transport stream of inserting the controlling packet processing, the scrambling randomization, coding and convolutional interleave are handled;
(f). the transport stream of handling through the coding and the convolutional interleave of standard is carried out single channel encryption handle, adopt the variable pseudorandom scrambling of initial state, its generator polynomial is g (x)=x
19+ x
5+ x
2+ x+1,11 bit address sign indicating numbers of control information and 8 bag count values are carried out scrambling to the transmission package between current controlling packet and the next controlling packet, not scrambling of controlling packet as 19 bit initial states after controlling packet of every insertion; To carry out the sign map and the modulation treatment of the cable digital TV of standard through the transport stream of encryption, send;
(g). in receiver, at first the transport stream that receives is carried out the demodulation process of the cable digital TV of standard, at this moment also do not make deinterleaving and channel decoding and handle, tentatively obtain digital signal from radiofrequency signal; In transport stream, pass through the transmission package packet header of examination criteria, identify transmission package one by one, then i the signal packet with the transmitting terminal agreement in 8 signal packet of every frame detected, if on the 13rd, 25,37,49,61,73,85,97,109,121,133,145,157,169,181 bytes of signal packet, identify the control information of prescribed form, the expression data flow is a legitimate traffic, normally receives data; If at a period of time t within second of regulation, fail to detect the appearance of the control information of prescribed form always, be indicated as invalid data stream, the rejection data, and continue to detect control information.
2. prevent the method for illegal broadcasting in the cable digital TV broadcasting according to claim 1, it is characterized in that: at 8 kinds of pre-scrambling modes described in the step (b), every kind of usefulness 16 system numbers are expressed as follows from the 1st byte to the 15 byte orders:
The 1st kind: 73 A1 2B B4 9D, 86 3B, 30 25 3A FB, 63 F7 EA 7D
The 2nd kind: 71 2E A7,84 32 A3,76 41 D8 DB, 19 CC 52 38 05
The 3rd kind: FC 56 91 50 68 CF 66 C7 1F 41 07 9D AA 97 58
The 4th kind: 56 37 E3 B6 9A 6A 9B, 53 08 56 6A, 45 2A A8 62
The 5th kind: D5 E8 DF B0 99 DF C4 53 74 63 58 99 29 EE D7
The 6th kind: 38 D4 DC, 73 73 52 C1 6F, 81 8A, 36 DA, 25 9F 08
The 7th kind: C1 98 94 1D 97 D2 7D 8A BE BA B5 53 00 A9 F3
The 8th kind: C2 D5 9E 6A 3D E0 D6 03 66 19 66 E1 33 96 E5.
3. according to the method that prevents illegal broadcasting in the described a kind of cable digital TV broadcasting of claim 1, it is characterized in that, described insertion controlling packet be spaced apart 2 milliseconds, corresponding to different transmission rates, insert a controlling packet in the transmission package of the multiple per 8; When being 6.528 MBPSs, the speed that requires the transport stream after process is inserted controlling packet in per 8 transmission package, inserts a controlling packet; When being 13.056 MBPSs, the speed that requires the transport stream after process is inserted controlling packet in per 16 transmission package, inserts a controlling packet; When being 19.584 MBPSs, the speed that requires the transport stream after process is inserted controlling packet in per 24 transmission package, inserts a controlling packet; When being 26.112 MBPSs, the speed that requires the transport stream after process is inserted controlling packet in per 32 transmission package, inserts a controlling packet; When being 39.168 MBPSs, the speed that requires the transport stream after process is inserted controlling packet in per 48 transmission package, inserts a controlling packet; When being 52.224 MBPSs, the speed that requires the transport stream after process is inserted controlling packet in per 64 transmission package, inserts a controlling packet.
4. according to the method that prevents illegal broadcasting in the described a kind of cable digital TV broadcasting of claim 1, it is characterized in that described receiving terminal is by detecting controlling packet, therefrom the cycle of extracting is 2 milliseconds a timing information, is used for Network Synchronization.
5. according to the method that prevents illegal broadcasting in the described a kind of cable digital TV broadcasting of claim 1, it is characterized in that, in described (c) the controlling packet production process in step, the bag sign of controlling packet that is used to carry control information is by transmitting terminal and receiving terminal agreement.
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| CN 03102681 CN1219401C (en) | 2003-02-14 | 2003-02-14 | A method for preventing illegal broadcasting in cable digital TV broadcasting |
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| CN 03102681 CN1219401C (en) | 2003-02-14 | 2003-02-14 | A method for preventing illegal broadcasting in cable digital TV broadcasting |
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| CN1219401C true CN1219401C (en) | 2005-09-14 |
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Families Citing this family (15)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2006035400A1 (en) * | 2004-09-30 | 2006-04-06 | Koninklijke Philips Electronics N.V. | Method of authentication based on polynomials |
| TWI273259B (en) * | 2004-11-09 | 2007-02-11 | Via Tech Inc | Built-in test architecture |
| CN100375508C (en) * | 2004-12-11 | 2008-03-12 | 陈小平 | Automatic anti-interference satellite digital broadcast television receiver |
| CN100484232C (en) * | 2005-06-03 | 2009-04-29 | 中国科学院研究生院 | Digital TV broadcast system and method |
| CN100484233C (en) * | 2005-06-03 | 2009-04-29 | 中国科学院研究生院 | Safety certification device for digital TV signal, and TV equipment with the device |
| TWI272853B (en) | 2005-09-21 | 2007-02-01 | Quanta Comp Inc | Image edge enhancement apparatus and method thereof |
| CN1937759B (en) * | 2005-10-31 | 2010-08-11 | 康佳集团股份有限公司 | In-hand key digital television signal encryption system |
| CN1972433B (en) * | 2005-11-25 | 2010-11-17 | 中国科学院研究生院 | Real-time authentication apparatus for digital TV transmission stream and television device with same |
| EP2040393A4 (en) * | 2006-06-19 | 2012-01-18 | Ntt Docomo Inc | Mobile communication system, mobile communication method, distribution server, radio line control station, and mobile station |
| CN101651549B (en) * | 2008-08-15 | 2012-09-05 | 威盛电子(中国)有限公司 | Multimedia broadcasting system, method and system for safely playing multimedia broadcasting contents |
| CN102164304B (en) * | 2011-02-23 | 2013-08-14 | 中国电子科技集团公司第三十六研究所 | Encrypting identification intercutting-preventing method for broadcasting program based on satellite transmission |
| CN102123001B (en) * | 2011-02-23 | 2012-11-21 | 浙江广播电视集团 | Inter-cut resisting system of digital satellite broadcasting (DSB) transmission |
| CN104581206A (en) * | 2013-10-23 | 2015-04-29 | 北京海格神舟通信科技有限公司 | Sound carrier coding-decoding and modulating-demodulating module |
| CN109005450B (en) * | 2018-07-16 | 2021-05-18 | 广州辉群智能科技有限公司 | Broadcast control method and device of broadcast equipment |
| WO2021102687A1 (en) * | 2019-11-26 | 2021-06-03 | 深圳瀚飞科技开发有限公司 | Communication encryption method and system |
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